TW202001263A - System having main supply and environment noise shielding capability for use in monitoring electrical characteristics of electrical cable and method for monitoring electrical characteristics of electrical cable - Google Patents

Abstract

The present invention particularly mainly discloses a system having main supply and environment noise shielding capability for use in monitoring electrical characteristics of electrical cable. Compared to the conventionally-used devices, this novel system shows the advantage of low set-up cost because of merely comprising a point measurement device, a signal generating device and a coupling capacitor. During the detection of the electrical characteristics of an electrical cable, the signal generating device is firstly configured to input a detection signal to the conductors of the electrical cable and the point measurement device, such that the point measurement device is able to receive a response signal from the shielding conductors. Subsequently, a degradation state or level of the electrical cable is therefore calculated by the point measurement device through comparing the detection signal with the response signal. In addition, the method proposed by the present invention can also be established through using mathematical algorithms, so as to be provided in an execution device like computer by a form of application program or operands.

Description

Cable measuring device and method with city power and environmental noise shielding

The invention relates to the technical field of cable, in particular to a cable measuring device and method for shielding city power and environmental noise.

According to the statistics of the research data, the Taiwan Electric Power Company had a total of 4027 accidents related to the underground power distribution system from 2003 to 2005, including 1,300 accidents involving high-voltage cables. At present, many countries have regarded cable detection and monitoring technology as one of the main focuses of national construction and development. Offline detection (off-line) is a traditional cable monitoring technology, which mainly uses a high resistance meter to measure the insulation resistance of at least one cable to be tested when the cable is disassembled. Due to the need to disassemble the cable, offline testing can only be performed at night. On the other hand, the disassembly and return of the cable to be tested usually depend on manpower. Therefore, it is necessary to spend a lot of manpower to complete the detection of the cable in the predetermined section within a limited time. It can be seen that how to detect the insulation resistance and leakage current of cables on-line has become the most important technical development goal of power companies.

FIG. 1 shows an architectural diagram of an insulation deterioration detection device disclosed in US Patent No. 9,335,380. As can be seen from FIG. 1, the insulation degradation detection device 101 ′ is electrically connected between a power supply device 1 ′ and a load 3 ′ controlled by a control device 2 ′, and includes: a zero-phase comparator (Zero-phase current transformer, ZCT) 4', a current transformer (CT) 5', a frequency calculation unit 7', a synchronous detection unit 8', and a display unit 9'; The current transformer 4'measures the leakage current flowing to the ground through the insulation resistance in the cable, and the current transformer 5'measures the phase current flowing to the load 3'through the cable. In addition, the frequency calculation unit 7'receives the phase current measured by the current transformer 5', and then performs frequency calculation. On the other hand, the synchronous detection unit 8'receives the leakage current (i.e., zero-phase current) measured by the zero-phase current transformer 4', and then performs Fourier conversion on the zero-phase current. Finally, the synchronous detection unit 8'is based on the phase current waveform and then removes the related noise from the zero-phase current. To put it simply, US Patent No. US9,335,380B2 mainly judges the degree of insulation deterioration of the cable according to the comparison result of zero-phase current and phase current.

Electronic engineers who have long been involved in the design and development of cable detection equipment should be able to find that the conventional cable deterioration detection equipment has the following practical use defects: (1) The frequency calculation unit 7'and the synchronous detection unit 8'must have a certain degree The calculation capability of the device causes the installation cost of the insulation degradation detection device 101' to be too high; and (2) The volume of the zero-phase current transformer 4'and the current transformer 5'change with the value of the phase current; conceivable It is known that all the units of the insulation deterioration detection device 101 ′ cannot be integrated into a single housing due to the excessively large zero-phase current comparator 4 ′ and current comparator 5 ′.

Establishing the electric thermal aging model of the cable is another commonly used detection method of cable insulation deterioration. For example, US Patent No. US8,775,151B2 discloses a distributed temperature detection system. The system mainly uses many optical fibers buried in the cable as temperature sensors, and these optical fibers are finally connected to an external electronic computing device. With this arrangement, the electronic computing device can receive the optical signal from the optical fiber, and establish an electrothermal aging model of the cable based on the optical signal, and then judge the degree of deterioration of the cable based on the estimated cable characteristics. However, it is a pity that the purchase cost of optical fiber is too high, resulting in cable manufacturers that are mainly operating medium and low-cost cable lines reluctant to manufacture cable lines containing optical fibers, making distributed temperature detection systems gradually lose their market competitiveness .

It can be seen from the above description that how to design an excellent cable insulation deterioration detection system under consideration of the computing power of the monitoring device and its installation cost has now become a very important subject. In view of this, the inventor of the present case tried his best to research and invent, and finally developed and completed a cable measurement device and method of the present invention with commercial power and environmental noise shielding.

The insulation degradation detection device provided by the conventional technology and the cable insulation degradation detection method achieved by using optical fibers both show the important defect that the installation cost is too high. Differently, the present invention proposes a cable measurement device and method for shielding mains and environmental noise, which is composed of only one point measurement module, a signal generation module and a coupling capacitor, so it has a low installation cost Advantage. In the detection of cable characteristics, a detection signal is input to the cable and the point measurement module through the signal generation module, so that the point measurement module can receive a feedback signal from the shielded conductor of the cable. Then, the point measurement module can calculate the degree of deterioration of the cable by comparing the detection signal and the feedback signal. In addition, the cable characteristic monitoring method of the present invention can also be built into an execution device, such as a computer, processor, or controller, in the form of a library, variable, or operand, thereby further revealing the present invention High flexibility in practical applications.

In order to achieve the above-mentioned main objective of the present invention, the inventor of the present invention provides an embodiment of the cable measuring device with mains and environmental noise shielding, which includes: a one-point measuring module, which is electrically connected to a cable A conductor and a shielding conductor; and a signal generation module electrically connected to the point measurement module and the conductor of the cable; wherein the signal generation module is used to input a detection signal to the cable and the A point measurement module so that the point measurement module can receive a feedback signal from the shielded conductor of the cable; wherein the point measurement module calculates the point by comparing the detection signal and the feedback signal The degree of deterioration of the cable.

In the foregoing embodiment of the cable measurement device, it further includes: a coupling capacitor coupled between the conductor and the shielding conductor; wherein, the detection signal transmitted in the conductor passes through the coupling capacitor Becomes the feedback signal, and the feedback signal is further transmitted to the point measurement module through the shielding conductor.

Moreover, in order to achieve the above-mentioned main objective of the present invention, the inventor of the present invention provides an embodiment of the cable measurement method, which includes the following steps: (1) Create a measurement module and a signal generation module on the execution device Group; and, the actuator is electrically connected to a conductor and a shielded conductor of a cable; (2) the signal generation module generates a detection signal, and the detection signal is input to the cable through the actuator The conductor and the point measurement module; (3) the detection signal transmitted in the conductor becomes a feedback signal through a coupling capacitor; (4) the execution device receives the feedback from the shielded conductor of the cable Signal, and provide the feedback signal to the point measurement module; and (5) the point measurement module calculates the degree of deterioration of the cable by comparing the detection signal and the feedback signal.

In the embodiment of the aforementioned cable measurement method, wherein the execution device is further established with: a communication interface electrically connected between the point measurement module and an electronic device, so that the point measurement The measurement module can send a measurement data to the electronic device.

In the foregoing embodiment of the cable measurement method, the method further includes the following steps: (6) The execution device transmits the measurement data of the cable to the electronic device through the communication interface.

In order to be able to more clearly describe a cable measurement device and method for shielding mains and environmental noise proposed by the present invention, the following will explain in detail the preferred embodiments of the present invention in conjunction with the drawings.

First embodiment

Before starting to explain a cable measuring device and method of the present invention with shielding of commercial power and environmental noise, the basic structure of the cable must be introduced first. Although an electrical engineer or an engineer with a motor background should be familiar with the basic structure of a cable, in order to allow relevant technicians to more easily understand the technical features of the present invention, the basic structure of the cable is simply described here. Figure 2 shows a side cross-sectional view of a conventional cable. The basic structure of the conventional cable 2 includes: an inner semiconducting layer 20 covered with a plurality of conductors CT, an insulating layer 23 covering the inner semiconducting layer 20, and an outer semiconducting layer covering the insulating layer 23 24, and an outer sheath 25 covering the outer semiconductor layer 24; wherein, a plurality of shielding conductors SC are embedded in the outer semiconductor layer 24.

FIG. 3 shows a structural diagram of a first embodiment of a cable measurement device with shielding of commercial power and environmental noise according to the present invention. As shown in FIG. 3, the cable measurement device 1 includes: a point measurement module 11, a signal generation module 12, and a coupling capacitor Cc; wherein, the point measurement module 11 is electrically connected to the cable 2 conductor CT and shielding conductor SC, and the signal generating module 12 is electrically connected to the point measurement module 11 and the conductor CT of the cable 2. On the other hand, the coupling capacitor Cc is coupled between the conductor CT and the shielding conductor SC. When performing cable characteristic monitoring, the present invention inputs a detection signal DS to the cable 2 and the point measurement module 11 through the signal generation module 12 at the same time, so that the point measurement module 11 can be received from the shielding conductor SC of the cable 2 A feedback signal RS. In this way, the point measurement module 11 can calculate the degree of deterioration of the cable 2 by comparing the detection signal DS and the feedback signal RS.

According to the design of the present invention, the point measurement module 11 includes a voltage measurement unit 111 and a phase measurement unit 112. Please refer to FIG. 4 and FIG. 5 at the same time; FIG. 4 is a circuit block diagram of the voltage measurement unit, and FIG. 5 is a circuit block diagram of the phase measurement unit. As can be seen from FIGS. 3 and 4, the voltage measurement unit 111 includes: a first band-pass filter BF1, a first low-pass filter LF1, a second band-pass filter BF2, and a second low-pass filter LF2 and a sample and hold circuit SH are mainly used to sample a first voltage and a second voltage signal from the detection signal DS and the feedback signal RS, respectively. In operation, the detection signal DS is input to the first band-pass filter BF1 of the voltage measuring unit 111, and is subjected to the band-pass filtering process of the first band-pass filter BF1. Furthermore, the detection signal DS is further input from the first band-pass filter BF1 to the first low-pass filter LF1, and subjected to the low-pass filtering process of the first low-pass filter LF1. Finally, the sample-and-hold circuit SH receives the detection signal DS that has completed two filtering processes, and samples the first voltage from the detection signal DS.

After the signal generating module 12 inputs the detection signal DS to the cable 2, the detection signal DS transmitted in the conductor CT passes through the coupling capacitor Cc and then becomes the feedback signal RS, and the feedback signal RS is further transmitted through the shielding conductor SC To this point measurement module 11. Next, the feedback signal RS is input to the second band-pass filter BF2 of the voltage measuring unit 111, and is subjected to the band-pass filtering process of the second band-pass filter BF2. Furthermore, the feedback signal RS is further input from the second band-pass filter BF2 to the second low-pass filter LF2, and subjected to the low-pass filtering process of the second low-pass filter LF2. Finally, the sample-and-hold circuit SH receives the feedback signal RS that has completed two filtering processes, and samples the second voltage signal from the feedback signal RS.

As can be seen from FIGS. 3 and 5, the phase measurement unit 112 includes: a third band-pass filter BF3, a third low-pass filter LF3, a fourth band-pass filter BF4, and a fourth low-pass filter LF4, and a phase detection circuit PD. In operation, the detection signal DS is input to the third band-pass filter BF3 of the phase measuring unit 112, and is subjected to the band-pass filtering process of the third band-pass filter BF3. Furthermore, the detection signal DS is further input to the third low-pass filter LF3 from the third band-pass filter BF3, and subjected to the low-pass filtering process of the third low-pass filter LF3. Finally, a phase detection circuit PD receives the detection signal DS that has completed two filtering processes, and detects a first phase from the detection signal DS.

After the signal generating module 12 inputs the detection signal DS to the cable 2, the detection signal DS transmitted in the conductor CT passes through the coupling capacitor Cc and then becomes the feedback signal RS, and the feedback signal RS is further transmitted through the shielding conductor SC To this point measurement module 11. Next, the feedback signal RS is input to the fourth band-pass filter BF4 of the phase measuring unit 112 and subjected to the band-pass filtering process of the fourth band-pass filter BF4. Furthermore, the feedback signal RS is further input from the fourth band-pass filter BF4 to the fourth low-pass filter LF4, and subjected to the low-pass filtering process of the fourth low-pass filter LF4. Finally, the phase detection circuit PD receives the feedback signal RS that has completed two filtering processes, and detects a second phase from the feedback signal RS.

Figure 6 shows the waveforms of the detection signal and the feedback signal. It can be seen from FIG. 6 that when the deterioration degree of the cable 2 is higher, the voltage difference between the first voltage V ₁ of the detected detection signal DS and the second voltage V _{2 of the} feedback signal RS will also be high; or, The phase value between the first phase θ ₁ of the detected detection signal DS and the second phase θ _{2 of the} feedback signal RS will also be high. In the future, the aging (deterioration) model of the cable 2 can be further established based on multiple measurement data of the detection signal DS and the feedback signal RS.

Second embodiment

7 is a schematic diagram showing a second embodiment of the cable measuring device of the present invention; and, FIG. 8 is a schematic perspective view showing a second embodiment of the cable measuring device of the present invention. Comparing FIG. 7 and FIG. 3, it can be found that the second embodiment of the cable measurement device 1 further includes a communication interface 13, which may be a wired communication interface or a wireless communication interface, which is electrically connected to the point for measurement Module 11. As can be seen from FIGS. 7 and 8, through the communication interface 13, the cable measurement device 1 can transmit related measurement data to an external electronic device 3, such as a desktop computer, a notebook computer, a smartphone , Smart watches, smart glasses, or tablet computers. It is worth noting that engineers who have been involved in firmware design and development for a long time should know that the aforementioned cable aging model can be integrated into a cable characteristic monitoring program and installed in an electronic device 3 such as a smart phone. In this way, when the engineering staff operates the smartphone and activates the cable characteristic monitoring program, the cable characteristic monitoring program will obtain relevant measurement data from the cable measurement device 1 through the communication interface 13 of the smartphone. Then, the cable aging model in the cable characteristic monitoring program can immediately calculate the current aging degree of the cable 2. Once the cable 2 needs to be replaced immediately due to excessive aging, the cable characteristic monitoring program will also issue a warning signal to inform the engineering personnel.

It must be emphasized that although FIGS. 7 and 8 mean that the cable measurement device 1 of the present invention is a hardware circuit, it should not be used to limit the implementation of the present invention. As well known to engineers who have long been involved in the development and design of digital filters, digital filters can also be programmed using mathematical algorithm software, and then be built on applications such as computers, libraries, variables or operands. Processor or controller. Therefore, the present invention also provides a cable measurement method that can be applied to an actuator; wherein the actuator is electrically connected to the cable 2.

Please refer to FIG. 9, which is a flowchart illustrating a cable measurement method of the present invention. As shown in FIGS. 8 and 9, the cable measurement method of the present invention includes the following main execution steps: Step S1: Create a point measurement module 11 and a signal generation module 12 in the execution device; and , The actuator is electrically connected to a conductor CT and a shielded conductor SC of a cable 2; Step S2: the signal generating module 12 generates a detection signal DS, and the detection signal DS is input to the actuator through the actuator The conductor CT of the cable 2 and the point measurement module 11; Step S3: The detection signal DS transmitted in the conductor CT passes through a coupling capacitor Cc to become a feedback signal RS; Step S4: The execution device The shielding conductor SC of the cable 2 receives the feedback signal RS and provides the feedback signal RS to the point measurement module 11; Step S5: The point measurement module 11 compares the detection signal DS with the The feedback signal RS calculates the degree of deterioration of the cable 2.

It is worth noting that if a communication interface 13 is established in the execution device at the same time, as shown in FIG. 9, the cable measurement method of the present invention will further perform step S6: when the execution device establishes a connection with an electronic device 3 , The execution device transmits the measurement data of the cable 2 to the electronic device 3 through the communication interface 13.

In this way, the above is a complete and clear description of the cable measurement device and method of the present invention with the shielding of commercial power and environmental noise; and, through the above, it can be seen that the present invention has the following advantages:

(1) The insulation degradation detection device provided by the conventional technology and the cable insulation degradation detection method achieved by using optical fibers both show important defects of excessive installation cost. Differently, the present invention proposes a cable measurement device 1, which is composed of only one point measurement module 11, a signal generation module 12, and a coupling capacitor Cc, so it has the advantage of low installation cost. In the detection of cable characteristics, a detection signal DS is input to the cable 2 and the point measurement module 11 through the signal generation module 12 so that the point measurement module 11 can be received from the shielding conductor SC of the cable 2 A feedback signal RS. Then, the point measurement module 11 can calculate the degree of deterioration of the cable 2 by comparing the detection signal DS and the feedback signal RS.

(2) In addition, the circuit architecture of the cable measuring device 1 of the present invention can also be built into an execution device in the form of a library, variable, or operand, such as a computer, processor, or controller, Thus, the high flexibility of the cable measurement device 1 of the present invention in practical applications is more apparent.

It must be emphasized that the above detailed description is a specific description of possible embodiments of the present invention, but this embodiment is not intended to limit the patent scope of the present invention, and any equivalent implementation or change without departing from the technical spirit of the present invention, Should be included in the patent scope of this case.

<Invention> 2‧‧‧Cable CT‧‧‧Conductor 20‧‧‧Inner semiconducting layer 23‧‧‧Insulation layer 24‧‧‧Outer semiconducting layer 25‧‧‧Outer sheath SC‧‧‧Shielded conductor 1 ‧‧‧Cable measuring device 11‧‧‧Point measuring module 12‧‧‧Signal generating module Cc‧‧‧Coupling capacitor DS‧‧‧ Detection signal RS‧‧‧Feedback signal 111‧‧‧Voltage measuring unit 112‧‧‧Phase measurement unit BF1‧‧‧First band-pass filter LF1‧‧‧First low-pass filter BF2‧‧‧Second band-pass filter LF2‧‧‧Second low-pass filter SH‧ ‧‧Sampling and holding circuit BF3‧‧‧third bandpass filter LF3‧‧‧third lowpass filter BF4‧‧‧fourth bandpass filter LF4‧‧‧fourth lowpass filter PD‧‧‧‧ Phase detection circuit V ₁ ‧‧‧ First voltage V ₂ ‧‧‧ Second voltage θ ₁ ‧‧‧ First phase θ ₂ ‧‧‧ Second phase 13‧‧‧Communication interface 3‧‧‧Electronic device S1- S5‧‧‧Step S6‧‧‧Step

＜Convention＞101′‧‧‧Insulation deterioration detection device 2′‧‧‧Control device 1′‧‧‧‧Power supply device 3′‧‧‧Load 4′‧‧‧‧Comparison of current comparator 5′‧‧‧‧ Flow device 7'‧‧‧ frequency calculation unit 8'‧‧‧ synchronous detection unit 9'‧‧‧ display unit

FIG. 1 is a structural diagram of an insulation deterioration detection device disclosed in US Patent No. 9,335,380; FIG. 2 is a side cross-sectional view of a conventional cable; FIG. 3 is a utility power and environmental noise shielding of the present invention Fig. 4 is a circuit block diagram of a voltage measurement unit; Fig. 5 is a circuit block diagram of a phase measurement unit; Fig. 6 is a circuit diagram of a detection signal and a feedback signal Waveform diagram; FIG. 7 is an architectural view showing a second embodiment of the cable measuring device of the present invention; FIG. 8 is a schematic perspective view showing a second embodiment of the cable measuring device of the present invention; and FIG. 9 is a display The invention is a flow chart of a cable measurement method.

2‧‧‧Cable

CT‧‧‧Conductor

SC‧‧‧Shielded conductor

Cc‧‧‧Coupling capacitor

1‧‧‧Cable measuring device

11‧‧‧point measurement module

111‧‧‧Voltage measurement unit

112‧‧‧Phase measurement unit

12‧‧‧Signal generation module

DS‧‧‧ detection signal

RS‧‧‧Feedback signal

Claims (10)

A cable measurement device includes: a one-point measurement module that is electrically connected to a conductor and a shielded conductor of a cable; and a signal generation module that is electrically connected to the point measurement module and the The conductor of the cable; wherein the signal generation module is used to input a detection signal to the cable and the point measurement module so that the point measurement module can receive a feedback signal from the shielded conductor of the cable; Wherein, the point measurement module calculates the deterioration degree of the cable by comparing the detection signal and the feedback signal. The cable measurement device as described in item 1 of the patent application scope, wherein the point measurement module includes: a voltage measurement unit for sampling a first from the detection signal and the feedback signal respectively A voltage and a second voltage signal; and a phase measuring unit for sampling a first phase and a second phase from the detection signal and the feedback signal, respectively. The cable measuring device as described in item 1 of the patent application scope further includes: a coupling capacitor coupled between the conductor and the shielding conductor; wherein the detection signal transmitted in the conductor passes through the coupling The capacitor then becomes the feedback signal, and the feedback signal is further transmitted to the point measurement module through the shielding conductor. The cable measurement device as described in item 1 of the patent application scope further includes: a communication interface electrically connected to the point measurement module to enable the point measurement module to transmit a measurement data To an electronic device. The cable measurement device as described in item 2 of the patent application scope, wherein the voltage measurement unit includes: a first band-pass filter for receiving the detection signal and performing band-pass filtering on the detection signal Processing; a first low-pass filter, electrically connected to the first band-pass filter, for subsequently performing low-pass filtering on the detection signal; a second band-pass filter, for receiving the feedback Signal, and band-pass filter the feedback signal; a second low-pass filter, electrically connected to the second band-pass filter, for low-pass filtering the feedback signal; and a sample The holding circuit is electrically connected to the first low-pass filter and the second low-pass filter, and is used to receive the detection signal and the feedback signal after completing two filter processing procedures, and from the detection signal and the The first voltage and the second voltage signal are sampled from the feedback signal, respectively. The cable measurement device as described in item 4 of the patent scope, wherein the communication interface is a wired communication interface or a wireless communication interface; and, the electronic device may be any of the following: desktop computer, notebook Computer, smart phone, smart watch, smart glasses, or tablet. The cable measurement device as described in item 5 of the patent application scope, wherein the phase measurement unit includes: a third bandpass filter for receiving the detection signal and performing bandpass filtering on the detection signal Processing; a third low-pass filter, electrically connected to the first band-pass filter, for performing a low-pass filtering process on the detection signal; a fourth band-pass filter, for receiving the feedback Signal, and band-pass filter the feedback signal; a fourth low-pass filter, electrically connected to the second band-pass filter, for low-pass filtering the feedback signal; and a phase The detection circuit is electrically connected to the third low-pass filter and the fourth low-pass filter, and detects the first phase and the second phase from the detection signal and the feedback signal. A cable measurement method includes the following steps: (1) A point measurement module and a signal generation module are established on the execution device; and, the execution device is electrically connected to a conductor and a shield of a cable Conductor; (2) the signal generation module generates a detection signal, and the detection signal is input to the conductor of the cable and the point measurement module through the execution device; (3) the detection transmitted in the conductor The signal passes through a coupling capacitor to become a feedback signal; (4) The execution device receives the feedback signal from the shielding conductor of the cable and provides the feedback signal to the point measurement module; and (5) The The point measurement module calculates the degree of deterioration of the cable by comparing the detection signal and the feedback signal. The cable measurement method as described in item 8 of the patent application scope, wherein the execution device is further established with: a communication interface electrically connected between the point measurement module and an electronic device, so that The point measurement module can send a measurement data to the electronic device. The cable measurement method described in item 9 of the patent application scope further includes the following steps: (6) The execution device transmits the measurement data of the cable to the electronic device through the communication interface.

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